This change treats 'top-level' collection-type models similarly to
top-level POCO model - namely that they will always be instantiated even
if there's no data to put inside.
The assumption is ModelState should have entries if
1. An error is explicitly added by a model binder.
2. There is validation error reported while validating the model.
3. There is value bound by the model binder.
With this change there should be no extra entry other than for the cases mentioned above.
Also enabling the integration test cases.
Ryan Nowak
Harsh Gupta
N. Taylor Mullen